How to Calculate a Weighted Average Grade

A simple average treats every mark as equally important. A weighted average is different: each assignment, test or exam contributes according to its percentage of the final result.

Quick answer: multiply each score by its weight, add the weighted results together and divide by the total weight.

The weighted-average formula

Weighted average = Σ(score × weight) ÷ Σ(weights)

Use weights as percentages or decimals, but stay consistent. If you use percentages, divide the final total by 100 when the weights add up to 100.

Worked course-grade example

Imagine a course with these components:

• Assignment: 80% score, worth 20% of the course
• Exam: 70% score, worth 50% of the course
• Project: 90% score, worth 30% of the course

The calculation is:

(80 × 0.20) + (70 × 0.50) + (90 × 0.30) = 16 + 35 + 27 = 78%

The weighted course result is therefore 78%.

How to calculate a weighted grade step by step

1. List each mark and its weighting.
2. Convert each weighting to a decimal if needed.
3. Multiply each mark by its weighting.
4. Add the weighted contributions.
5. Check that the weightings total 100% or that you divide by the total weight.

The Weighted Grade Calculator can help when your assessment components have different weights.

Weighted average versus simple average

If three marks are 60%, 70% and 80%, a simple average is 70% because each mark has equal importance. If the 60% mark is worth 50% of the course and the other two marks are worth 25% each, the weighted result will be different because the largest assessment has the greatest effect.

What if the weights do not add to 100%?

For a complete course result, the weights should normally represent all assessed work and total 100%. If you are averaging only part of a record, use the total of the included weights as the denominator and label the result clearly as a partial weighted average.

Planning your final exam mark

Once you know your current weighted result, the Final Grade Calculator can help you estimate the mark needed on a remaining exam to reach a target course grade. Use the weighting shown in your official course outline.

Common mistakes

• Adding raw marks without applying their weights.
• Mixing percentages and decimals in the same calculation.
• Forgetting an assessment component.
• Using a target course grade as if it were the required exam mark.

For a quick check, compare your work with the Weighted Average Grade Calculator and verify the result against your institution’s grading rules.